^"^reb^'iSf''"'}        jBorocitrates  and  their  Preparation.  67 
citric  acid^  20  parts  ;  lithium  carbonate,  7  parts ;  crystallized  boric  acid, 
12  parts. 
c.  Lithium  Monoborocitrate  (CgHgLi(B0)07)  +  H2O. — Crystallized 
citric  acid,  20  parts  ;  lithium  carbonate,  4  parts ;  crystallized  boric  acid, 
6  parts. 
Sodium  Borocitrates. — The  normal  salt  of  sodium  and  both  acid 
salts  are  obtained  by  decomposition  of  crystallized  sodium  carbonate. 
a.  Sodium  Triborocitrate  (CgH-NagO^  -|-  BgHgOg),  etc. — Crystallized 
citric  acid,  21  parts;  crystallized  sodium  carbonate,  42  parts;  crystal- 
lized boric  acid,  18  parts. 
b.  Sodium  Diborocitrate. — Citric  acid,  20  parts;  sodium  carbonate, 
28  parts;  boric  acid,  12  parts. 
c.  Sodium  Monoborocitrate. — Citric  acid,  20  parts;  sodium  carbon- 
ate, 14  parts;  boric  acid,  6  parts. 
A  sodium  compound  prepared  by  Schering,  of  Berlin,  occurs  as  a 
light  powder,  easily  soluble  in  water,  having  an  agreeable  acid  taste, 
and  in  its  composition  standing  nearest  to  the  monoborocitrate.  An 
analysis  gave  the  following  percentage  composition:  citric  acid,  80*15; 
sodium,  8*77;  boric  acid,  11*08. 
Ammonium  Borocitrates. — The  ammonium  salts  are  most  suitably 
prepared  from  the  ammonium  carbonate.  The  compounds  must  be 
carefully  dried,  since  otherwise  decomposition  gradually  takes  place, 
ammonia  being  volatilized. 
a.  Ammonium  Triborocitrate  CQH.^{lSH^)fi^  ^  BgHgOg,  etc. — Citric 
acid,  20  parts;  ammonium  carbonate,  15  parts;  boric  acid,  18  parts. 
b.  Ammonium  Diborocitrate. — Citric  acid,  20  parts;  ammonium  car- 
bonate, 10  parts;  boric  acid,  12  parts. 
c.  Ammonium  Monocarbonate. — Citric  acid,  20  parts;  ammonium 
carbonate,  5  parts ;  boric  acid,  6  parts. 
A  preparation  made  by  Schrenk,  in  Darmstadt,  has  almost  the  same 
composition  as  the  normal  ammonium  triborocitrate.  It  consists  of 
citric  acid,  51*38  per  cent.;  ammonium  (N^HJ,  14  per  cent.;  boric  acid, 
34*62  per  cent. 
Potassium  Borocitrates. — The  potassium  compounds  have  up  to 
the  present  time  found  scarcely  any  therapeutic  use,  but  are,  as  for 
instance,  the  crystalline  potassium  biborocitrate, — of  greater  theoretic 
value.  In  this  case  the  mono-  or  bicarbonate  of  potassium  are  best 
used  in  the  preparation. 
a.  Potassium   Triborocitrate  (CgH^KgO^  -|-   BgHgOg),  etc. — Citric 
